1. Field of the Invention
This invention is directed to novel compositions comprising one or more pentamantanes. This invention is also directed to novel processes for the separation and isolation of pentamantane components into recoverable fractions from a feedstock containing one or more pentamantane components.
2. References
The following publications and patents are cited in this application as superscript numbers:                1Lin, et al., Natural Occurrence of Tetramantane (C22H28), Pentamantane (C26H32) and Hexamantane (C30H36) in a Deep Petroleum Reservoir, Fuel, 74(10):1512-1521 (1995)        2 Alexander, et al., Purification of Hydrocarbonaceous Fractions, U.S. Pat. No. 4,952,748, issued Aug. 28, 1990        3 McKervey, Synthetic Approaches to Large Diamondoid Hydrocarbons, Tetrahedron, 36:971-992 (1980).        4 Wu, et al., High Viscosity Index Lubricant Fluid, U.S. Pat. No. 5,306,851, issued Apr. 26, 1994.        5 Chung et al., Recent Development in High-Energy Density Liquid Fuels, Energy and Fuels, 13; 641-649 (1999).        6 Sandia National Laboratories (2000), World's First Diamond Micromachines Created at Sandia, Press Release, (Feb. 22, 2000) www.Sandia.gov.        7 Balaban et al., Systematic Classification and Nomenclature of Diamondoid Hydrocarbons-I, Tetrahedron. 34, 3599-3606 (1978).        8 Chen, et al., Isolation of High Purity Diamondoid Fractions and Components, U.S. Pat. No. 5,414,189 issued May 9, 1995.        
All of the above publications and patents are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent was specifically and individually indicated to be incorporated by reference in its entirety.
3. State of the Art
Pentamantanes are bridged-ring cycloalkanes. They are the face-fused pentamers of adamantane (tricyclo[3.3.1.13,7]decane) or C10H16. The compounds have a “diamondoid” topology, which means their carbon atom arrangement is superimposable on a fragment of the diamond lattice (FIG. 1). There are ten possible pentamantanes (FIG. 2). Nine of the ten have the molecular formula C26H32. Among these nine, there are three pairs (six pentamantanes) that are enantiomers. In addition, there exists one condensed pentamantane represented by the formula C25H30.
Very little published work is available for pentamantanes and higher molecular weight diamondoids. Pentamantane compounds have not been artificially synthesized and these compounds have been recently thought only to have a theoretical existence.1,7 Academic chemists have primarily focused research on the interplay between physical and chemical properties in lower diamondoids such as adamantane, diamantane and triamantane. Adamantane and diamantane, for instance, have been studied to elucidate structure-activity relationships in carbocations and radicals.3 Process engineers have directed efforts toward removing lower diamondoids from hydrocarbon gas streams.2 These compounds cause problems during the production of natural gas by solidifying in pipes and other pieces of equipment.
The literature contains little information regarding the practical application of pentamantanes. This fact is probably due to extreme difficulties with their isolation and failed synthesis attempts. Lin and Wilk, for example, discuss the possible presence of pentamantanes in a gas condensate.1 The researchers postulate the existence of the compounds based on a mass spectrometric fragmentation pattern. They did not, however, report the isolation of a single pentamantane. McKervey et al. discuss an extremely low-yielding synthesis of anti-tetramantane.3 The procedure involves complex starting materials and employs drastic reaction conditions (e.g., gas phase on platinum at 360° C.). Although one isomer of tetramantane, i.e. anti-, has been synthesized through a double homologation route, these syntheses are quite complex reactions with large organic molecules in the gas phase and have not led to the successful synthesis of other tetramantanes. Similar attempts using preferred-ring starting materials in accordance with the homologation route, has likewise failed in the synthesis of pentamantanes. Likewise, attempts using carbocation rearrangement routes employing Lewis acid catalysts, useful in synthesizing triamantane and lower diamondoids, have been unsuccessful in synthesizing pentamantanes.
Among other properties, diamondoids have by far the most thermodynamically stable structures of all possible hydrocarbons that possess their molecular formulas due to the fact that diamondoids have the same internal “crystalline lattice” structure as diamonds. It is well established that diamonds exhibit extremely high tensile strength, extremely low chemical reactivity, electrical resistivity greater than aluminum trioxide (Al2O3) and excellent thermal conductivity.
In addition, based on theoretical considerations, the pentamantanes have sizes in the nanometer range and, in view of the properties noted above, the inventors contemplate that such compounds would have utility in micro- and molecular-electronics and nanotechnology applications. In particular, the rigidity, strength, stability, thermal conductivity, variety of structural forms and multiple attachment sites shown by these molecules makes possible accurate construction of robust, durable, precision devices with nanometer dimensions. The various pentamantanes are three-dimensional nanometer-sized units showing different diamond lattice arrangements. This translates into a variety of rigid shapes and sizes for the ten pentamantanes. For example, [1212] pentamantane is rod shaped, [1(2,3)4] pentamantane has a pyramidal structure while [1231] is disc shaped. The two enantiomers of [1234] have left and right handed screw-like structures. It has been estimated that MicroElectroMechanical Systems (MEMs) constructed out of diamond should last 10,000 times longer than current polysilicon MEMs, and diamond is chemically benign and would not promote allergic reactions in biomedical applications.6 Again, the inventors contemplate that pentamantane would have similar attractive properties. Furthermore, some of the isomers of pentamantane possess chirality, offering opportunities for making nanotechnology objects of great structural specificity with useful optical properties. Applications of these pentamantanes include molecular electronics, photonic devices, nanomechanical devices, nanostructured polymers and other materials.
Notwithstanding these advantages of pentamantanes, the art, as noted above, fails to provide for compositions comprising pentamantanes. In view of the above, there is an ongoing need in the art to provide for compositions comprising one or more pentamantanes.